jamesp
Cave Dweller
Member since October 2012
Posts: 36,641
|
Post by jamesp on Nov 25, 2022 10:51:17 GMT -5
The New Madrid quakes and 1811 comet. www.anamericanquilt.com/the-great-comet.htmlInteresting geological effects, check out the quartz crystal luminescence: "The world's largest sand boil was created by the New Madrid earthquake. It is 1.4 miles long and 136 acres in extent, located in the Bootheel of Missouri, about eight miles west of Hayti, Missouri. Locals call it "The Beach." Other, much smaller, sand boils are found throughout the area. Seismic Tar Balls; Small pellets up to golf ball sized tar balls are found in sand boils and fissures. They are petroleum that has been solidified, or "petroliferous nodules.” Earthquake Lights; Lights flashed up from the ground, caused by quartz crystals being squeezed. The phenomena is called “seismoluminescence."" Powerful earthquake: "The area of strong shaking associated with these shocks was two to three times larger than that of the 1964 Alaska earthquake and 10 times larger than that of the 1906 San Francisco earthquake. The midwest experienced more than 2,000 earthquakes in five months, people discovered that most of crevices opening up during an earthquake ran from north to south and they would chop down trees in an east- west direction using the trees as a bridge. There were "missing people" who were most likely swallowed up by the earth. Some earthquake fissures were as long as five miles." Long lasting and reached far: " The New Madrid earthquakes were the biggest earthquakes in American history. They occurred in the central Mississippi Valley, but were felt as far away as New York City, Boston, Montreal, and Washington D.C. President James Madison and his wife Dolly felt them in the White House. Church bells rang in Boston. From December 16, 1811 through March of 1812 there were over 2,000 earthquake aftershocks in the central Midwest, and between 6,000-10,000 earthquakes in the Bootheel of Missouri where New Madrid is located near the junction of the Ohio and Mississippi Rivers. In the known history of the world, no other earthquakes have lasted so long or produced so much evidence of damage as the New Madrid earthquakes. Three of the earthquakes are on the list of America's top earthquakes: the first one on December 16, 1811, a magnitude of 8.1 on the Richter scale; the second on January 23, 1812, at 7.8; and the third on February 7, 1812, at as much as 8.8 magnitude."
|
|
|
Post by Starguy on Nov 25, 2022 11:04:51 GMT -5
Great post. I’ve always been fascinated by the New Madrid quake.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,641
|
Post by jamesp on Nov 25, 2022 14:21:15 GMT -5
Great post. I’ve always been fascinated by the New Madrid quake. Due to the thick layer of contiguous solid bedrock close to the surface under the eastern US tremors and shock waves travel long distances transmitting their energy well Brent. Said shallow bedrock is the target for high rise building foundations. In Atlanta they will dig 30 to 50 feet of clay out of a foundation hole and set the high rise directly on the granite bedrock. This certainly prevents settling but makes the tall buildings vulnerable to horizontally born shock waves.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,070
|
Post by gemfeller on Nov 25, 2022 15:24:32 GMT -5
jamesp "Earthquake Lights; Lights flashed up from the ground, caused by quartz crystals being squeezed. The phenomena is called “seismoluminescence." That's a pretty simplified explanation for the phenomenon. The process you describe is called piezoelectricity. But it's only one of multiple theories for why the lights occur. The following Wikipedia article covers several others, as well as some critics who say the event doesn't exist. I can tell those critics to take a long walk off a short pier because I witnessed it personally during California's Northridge Earthquake in 1994. The ground started shaking violently, waking my wife and I from a sound sleep. Our bedroom windows lit up with bright flashes resembling sheet lightning strikes. My wife managed to get near the windows to watch it and I had to grab her and pull her away for fear the window glass would shatter and hurt her. It was quite a show and it lasted until the ground quit shaking. I've wondered what caused it ever since and have done a little research but can't find a lot about it. Accounts vary, as per the following: en.wikipedia.org/wiki/Earthquake_light
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,641
|
Post by jamesp on Nov 26, 2022 10:32:16 GMT -5
jamesp "Earthquake Lights; Lights flashed up from the ground, caused by quartz crystals being squeezed. The phenomena is called “seismoluminescence." That's a pretty simplified explanation for the phenomenon. The process you describe is called piezoelectricity. But it's only one of multiple theories for why the lights occur. The following Wikipedia article covers several others, as well as some critics who say the event doesn't exist. I can tell those critics to take a long walk off a short pier because I witnessed it personally during California's Northridge Earthquake in 1994. The ground started shaking violently, waking my wife and I from a sound sleep. Our bedroom windows lit up with bright flashes resembling sheet lightning strikes. My wife managed to get near the windows to watch it and I had to grab her and pull her away for fear the window glass would shatter and hurt her. It was quite a show and it lasted until the ground quit shaking. I've wondered what caused it ever since and have done a little research but can't find a lot about it. Accounts vary, as per the following: en.wikipedia.org/wiki/Earthquake_light That had to be a truly unforgettable experience for you guys. The lights must have been substantial for them to be noticed in the midst of the excitement of the quake. The ice storm of 1973 at Atlanta Ga. lit up the skies in colors throughout the spectrum due to pole and large substation mounted transformers exploding throughout the night. Modern earthquakes could be responsible for similar. But there were few utilities in 1811 during the New Madrid quake yet these sightings were reported even from long distances: Lights caused by the 1811/12 New Madrid quake before utilities: "The stronger shocks were followed by black clouds or darkness from the “smoke”, “fog”, or “vapor” that took hours to clear. The darkness was likely dust from the land slides and collapsed structures. Water vapor released from the ground condensed in the cold winter atmosphere creating an “earthquake fog”. One of the most mysterious and disputed claims related to the New Madrid quakes was from several reputable witnesses who saw lightning-like flashes and glows in the sky that directly accompanied the quakes. One person in New Madrid reported sparks emitted from the earth. (For more on earthquake lights, see this post.) William Pierce, who wrote letters to the New York Evening Post reporting back from his journey along the Mississippi said that “an electric flash ran along the surface tearing the earth to pieces in its progress”. Flashes and a glowing sky were also seen from those in distant cities. The atmosphere was said to be luminous across the entire sky at night even though there was no moon. Red clouds were seen in South Carolina immediately before the Dec 16 quake. In North Carolina, people reported long-lasting sky glow that they thought was the result of large fires. Loud thunder accompanied the glow. A report from ships in the tropics noted aurora-like glows in the sky one night. Later, they correlated that observation to the time of a quake. Scientists historically dismissed these reports of lights by assuming they were related to the dust and water vapor emitted along the fault, thunderstorms, or regular atmospheric magnetic disturbances. But the curious possibility remains that earthquake lights may have manifested from the ground or in the atmosphere resulting from the fault movements." Oddly Tecumseh's Comet showed itself in the skies for 260 days during the 5 month period of Madrid quakes and tremors.
|
|
|
Post by Starguy on Nov 26, 2022 11:43:19 GMT -5
What an interesting thread! I’ve always found earthquakes fascinating. I’ve been lucky enough to experience several. Each time I’ve felt an earthquake, I seemed to sense some atmospheric energy immediately before and after feeling the tremors. I chalked it up to potential energy stored in the crust but maybe some of the potential is released as static ahead of and behind the seismic waves. I would describe the sensation as having the hair on my arms stand on end. Another interesting thing I’ve noticed is that you can hear the quake moving away from you. I can’t say that I heard the waves coming ahead of time though. I suspect seismic waves in the crust move faster than the speed of sound.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,070
|
Post by gemfeller on Nov 26, 2022 12:46:02 GMT -5
Earthquakes are interesting but also very scary. The Northridge quake seemed to rumble on for a good minute or so. It seemed like an eternity. The lights went out almost immediately, leaving the eerie flashes of light outside as the only intermittent illumination. I tried to get out of the bedroom to see if there was any damage and it was like walking on moving basketballs.
But the worst were the aftershocks, and not knowing whether the Big One was yet to come. I tried to get a little sleep but was awakened frequently by tremors. The next morning I was sitting at the kitchen table when a big aftershock slammed he house. I think it was a little over 5 on the Richter Scale. I watched the kitchen cupboard move out at least a foot from its normal position. But not a single dish was broken or moved from its place; it all moved as a unit.
Some years earlier we lived near Pismo Beach, just across the bay from the Diablo Canyon Nuclear Power Plant. There was an elaborate system of warning sirens set up to warn residents of any nuclear accident. When the big Loma Prieta quake hit the San Francisco Bay Area in 1989 we felt one big shock even though we were many miles away. We had guests and we took them to an early dinner at one of the local restaurants. While dining, the Diablo sirens all began to wail. I felt certain it was earthquake-related. I also knew that if it was a Diablo accident we were probably already goners, given the short distance from the plant and prevailing winds. Our guests were terrified and I was unable to reassure them. It made for a difficult social situation.
We were later relieved to learn that the incident was, indeed, related to the quake. But we were reminded just how thin the dividing line is between normal, happy, daily life and disaster.
|
|
|
Post by Starguy on Nov 26, 2022 13:46:27 GMT -5
gemfeller. The earthquakes I’ve been in were pretty small. They are relatively common in central Idaho. I’ve never experienced large ones like you did in California. We had one near Stanley a couple years ago. I was sitting in the recliner and I thought my wife was shaking the chair. She was actually in the basement. When I noticed some mobiles and hanging lights continue to swing, I knew we had experienced an earthquake. I estimated 6-8 seconds of shaking. When I went to the basement to check on my wife, she hadn’t even felt it.
|
|
|
Post by mohs on Nov 26, 2022 19:20:46 GMT -5
never knew about these events
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,070
|
Post by gemfeller on Nov 26, 2022 19:37:37 GMT -5
gemfeller . The earthquakes I’ve been in were pretty small. They are relatively common in central Idaho. I’ve never experienced large ones like you did in California. We had one near Stanley a couple years ago. I was sitting in the recliner and I thought my wife was shaking the chair. She was actually in the basement. When I noticed some mobiles and hanging lights continue to swing, I knew we had experienced an earthquake. I estimated 6-8 seconds of shaking. When I went to the basement to check on my wife, she hadn’t even felt it. My wife worked for Morrison-Knudsen construction company in Boise prior to our moving to California years ago. M-K has an office building several stories high. When we moved her co-workers teased about her going to "earthquake country." Some months later they were singing a different tune when their building started swaying violently during the Mt. Borah 6.9 quake not far from Challis. It was the strongest on record in ID. On a trip to ID several years ago we visited the fault scarp and it is awesome in size. Part of ID decided to move south toward NV, in a continuing tectonic plate adjustment. All of central ID is subject to big quakes. Remember: the Yellowstone Hot Spot used to sit in WA state, then OR, then it cut a violent volcanic swath through what is now the Snake River Plain in southern ID and -- for now -- is situated mostly in WY. But the hot spot didn't move at all: he earth (plate) did.
|
|
|
Post by 1dave on Nov 26, 2022 20:21:29 GMT -5
Electricity and Magnetism are opposite sides of the same coin. You can't have one without the other. Remember the Right Hand Rule. What causes alternating current and magnetism in shockwaves alternating at thousands of times per second? Electron path between two sand grains. That is what also created the iron filled sandstone joints and Moqui Marbles in Big Spencer Flat.
|
|
|
Post by Starguy on Nov 27, 2022 10:56:26 GMT -5
gemfeller Rick We have friends in Boise. Their stories are pretty funny about the last central Idaho earthquake. Apparently Boise felt it much stronger than we did. I was still in college in Moscow when the Mount Borah quake took place. It woke me up from a dead sleep. If I remember, that quake raised the elevation of Mount Borah by about eight feet. I need to go look at that scarp before erosion completely obliterates it. I’ve seen pictures of it. It’s an unimaginable amount of energy released in even the smallest quakes. With all of the mines in the Silver Valley, we hear about rock bursts regularly. They are picked up on seismographs but I have never felt one. I worked with Morrison Knudsen on a couple aspects of a bridge repair contract. It’s a highly reputable company.
|
|